A method is provided in which a base design is generated in the form of one or more data files including assignment data. A variation design is created by adding at least one additional assignment associated with the variation design to the assignment data. The assignment data has an identifier that is associated with an entity defined within the base design, a first data field that can be used in making an assignment to the entity within the base design and a second data field for use in making the additional assignment to the entity within the variation design. The data files are compiled to generate a base output file and one or more variation output design files that can include one or more common result values. Comparison data is generated by comparing the common result values associated with the base design file and the variation design file. A design tool is provided for use with a computer system having a processor. The design tool includes a selector and a variation mechanism. Both the selector and variation mechanism are configured to run on the processor and are capable of accepting inputs from a user. The selector generates a base design in the form of one or more data files including assignment data. The variation mechanism generates a variation design by adding at least one additional assignment associated with the variation design.